This invention relates generally to the manufacture of ophthalmic lenses and more particularly concerns the application of universal blocks to any of wide variety of lens contours.
Presently known lens blocking procedures typically involve the application of a preformed block to the surface of the lens. While preformed blocks assure identicity of their adapter surface with the surface of the adapter to be used, preformed blocks cannot be universal to all lenses. As a result, the contour of the surface of any given lens rarely flushes with the contour of the block applied to the lens. It is, therefore, common practice to build up the lens surface to accommodate the contour of the block. In addition to the added time and labor involved in this individualized blocking process, materials also pose a problem. Unfortunately, known build-up processes generally involve use of alloys which give rise to operator safety and environmental protection complications. In addition, the build-up processes generally involve the exercise of operator judgment in assessing the amount of build up necessary for each lens. Such subjective decision making does not foster consistency in the quality of block application. These problems are compounded by the need to apply different blocks to the same lens for the lens surfacing and finishing processes. Moreover, the application of build-up materials to the lens with the superimposition of the preformed block over the build-up generally makes inspection of the blocked lens after surfacing for optical power and center thickness difficult, if not impossible, without removal of the block from the lens.
It is, therefore, an object of this invention to provide a block-making machine and process for manufacturing an alloy less block for the lens industry. Another object of this invention is to provide a block-making machine and process for a universal block applicable to all radii on its lens contact surface. A further object of this invention is to provide a block-making machine and process for a universal block having a single common radius on its reverse or adapter contact side. Yet another object of this invention is to provide a block-making machine and process for a block which serves as both a surfacing and finishing block. Still another object of this invention is to provide a block-making machine and process for a block allowing optical power and center thickness inspection without removing the block. And it is an object of this invention to provide an automated method of forming and attaching a block to any lens.